Mom's Healthy Diet Might Cut Birth Defect Risk

MONDAY Oct. 3, 2011 -- Pregnant women who eat a healthy diet appear to reduce the risk of having a baby with a major birth defect, such as spina bifida or a cleft lip or palette, a new study suggests.

Neural tube birth defects -- including spina bifida and other brain abnormalities -- are known to decrease when pregnant women take supplements of folic acid, a type of vitamin B that also has been added to a variety of foods. However, folic acid alone does not prevent all birth defects, the researchers said.

"There may be certain qualities of foods that have benefits that aren't captured by examining just one nutrient at a time," said lead researcher Suzan L. Carmichael, an associate professor of pediatrics at Stanford University.

Diet could also be related to reducing birth defects because a combination of nutrients from a variety of foods may act together in a beneficial way, Carmichael said. "It is also possible that a healthy diet is a marker for other characteristics of a woman's lifestyle.

"Our study supports recommendations that have been made for many years for pregnant women," she said. "Eat a variety of foods, include a lot of fruits and vegetables and whole grains in your diet and take a vitamin supplement that contains folic acid."

Although folic acid can prevent up to 40 percent of neural tube defects, it's not the whole story, Carmichael said. "Babies are still born with neural tube defects, so we need to keep looking for answers," she said.

The report was published in the Oct. 3 online edition of the Archives of Pediatrics & Adolescent Medicine.

Using data from the U.S. National Birth Defects Prevention Study for October 1997 through December 2005, Carmichael's team looked at the role diet plays in birth defects. During telephone interviews, mothers described their diet.

The researchers looked at cases of 936 infants born with neural tube defects, 2,475 with oral clefts, and compared these with 6,147 infants without birth defects.

They found that women with diets similar to the Mediterranean Diet -- which is rich in fruits, vegetables, whole grains and fish and light in fats and sugar -- or the Food Guide Pyramid of the U.S. Department of Agriculture were at lower risk of having a baby with a neural tube defect or oral cleft, compared to women who reported eating less-healthy diets.

This finding remained even after adjusting for other factors such as taking a vitamin or mineral supplement, the researchers noted. "We found that diet was important whether a women took a vitamin supplement or not," Carmichael said.

Most women who gave birth to an infant who did not have a birth defect were white and had more than a high school education, the researchers found. Among mothers in the survey, 19 percent smoked, 38 percent drank, 78 percent took folic acid supplements and 16 percent were obese.

David R. Jacobs, Jr., the Mayo Professor of Public Health at the University of Minnesota in Minneapolis, and co-author of an accompanying journal editorial, said, "We have confused the constituents of food with food itself. Food is a complex mixture."

There may be a number of right ways to eat, and some diets that are not so good, he said. Generally, foods are better than supplements except when there is a deficiency, he added.

Jacobs noted that foods are more complex than drugs that contain only a single element and have been tested. "Food are not well understood," he said.

"There are some better ways to eat and supplements are probably not the right answer -- we should eat food," Jacobs said. One should not eat too much and eat mostly plants, he added.

Commenting on the study, Gail Harrison, a professor of public health at the University of California, Los Angeles, and spokeswoman for the March of Dimes, said, "I am not surprised that there is an independent effect of total diet quality."

The finding underscores the importance of the mother's nutrition both before and during pregnancy and the effect it can have on the developing infant, she said. "A lot that goes on that determines pregnancy outcome goes on very early in the pregnancy -- before women even realize they're pregnant," she said.

Harrison noted that healthy eating needs to start even before pregnancy. "Women who are capable of becoming pregnant really need to pay attention to overall diet quality," she said.